Smootables

School timetabling

How to build an exam timetable without clashes

A practical guide to building a school or college exam timetable: the inputs you need, the build order, and how JCQ's rules resolve candidate clashes, with the scope of those rules made explicit for centers outside England, Wales, and Northern Ireland.

Juho Isola, Smootables founder

This guide is for the person who builds a school or college's exam timetable: an exams officer, a head of exams, or a deputy head covering the role. It is not about looking up when your own exam is; if that's what you need, your center's exams office publishes your personal timetable, not a search engine.

Building the timetable means starting from every candidate's entries, placing each exam into a session against the awarding bodies' published key dates, and resolving the clashes that placement creates, all before a single candidate sees their timetable. The published, center-specific timetables that dominate search results for this topic are the *output* of that process, not a guide to doing it.

The build order in Steps 1, 2, 4, and 5 (entries, clash-finding, room allocation, publishing) holds for any exam system. Step 3's clash-resolution mechanics are JCQ's, so they apply directly if you run GCSEs or A-levels in England, Wales, or Northern Ireland; if you don't, read Step 3 as a worked example of what a clash policy specifies, then use your own awarding body's published rules in its place.

Key takeaways

  • Build the exam timetable from entries and the awarding bodies' published key dates, not from last year's grid.
  • Find clashes early. A clash is one candidate entered for two exams at the same time on the same day, and how you resolve it depends on how long the exams run and how many fall on that day.
  • This guide's clash-resolution steps follow JCQ's rules, the shared rulebook England, Wales, and Northern Ireland's GCSE and A-level exam boards publish together: some clashes move within the day, some move to the next morning (including Saturday), and a few subjects and situations cannot move at all.
  • Room and invigilator capacity are limits on the build, not a check you run after placing exams.
  • Confirm every clash resolution with the candidate in writing before the exam, not on the day.

Before you build: three inputs

  1. Entries, confirmed. Every candidate's subjects and qualification level (GCSE, AS, A level, or an equivalent), amended for late changes and withdrawals before the timetable is drafted, not after.
  2. The awarding bodies' key dates and JCQ's shared rules. JCQ, the Joint Council for Qualifications, is the body AQA, OCR, Pearson Edexcel, WJEC, CCEA, City & Guilds, and NCFE set up to publish one shared set of administration rules, including how a clash is resolved, so a center isn't reconciling five different boards' instructions during the same series. JCQ and the awarding bodies publish the key dates for each exam series; these are read-only, not something your center sets, and every clash-resolution rule in Step 3 is written against them. Scotland's National 5, Higher, and Advanced Higher exams run under a separate system, the SQA's (from 2026, Qualifications Scotland's), with its own timetable and clash process, not JCQ's.
  3. Room and invigilator capacity. How many candidates each usable room holds under exam conditions, and how many invigilators are actually available for the series, not just contracted. A timetable that ignores this until placement is finished restarts once it meets the real numbers.

Step 1: Draft against the published key dates

Place each candidate's exams onto the key dates the awarding bodies have already fixed for the series. This step does not resolve anything; it only reveals what needs resolving; the draft's job is to be complete enough that every clash it contains is a real one, not a placeholder gap.

Step 2: Find every clash

A clash is a candidate entered for two or more exams at the same time on the same day. A center with a management information system can usually run a clash report; without one, check manually against the draft. Do this with real time to spare: a clash found the week before a series limits you to the options below, and a clash found on the day does not.

Step 3: Resolve clashes under JCQ's rules

JCQ's guidance on managing timetable clashes (last updated February 2024) sets out exactly how a clash is resolved, and the mechanism depends on how long the exams run and how many a candidate has that day:

  • Same session, three hours or less combined. The candidate sits both exams consecutively in the same session; staff may order the papers and allow a supervised break of no more than twenty minutes between them.
  • Same session, over three hours combined. One exam moves to the other session on the same day. This needs no permission or paperwork from the awarding body.
  • Three or more exams the same day, totaling more than six hours (AS or A level) or five and a half hours (GCSE). One afternoon exam moves to the following morning, which can be a Saturday. This variation needs forms completed through JCQ's Centre Admin Portal and signed declarations from the candidate, the supervisor, and the head of center, because the candidate is under center supervision between the exams.
  • What cannot move. Variations are not permitted across a holiday, across different awarding bodies' clashing exams, or for AS or A level Mathematics, which cannot be moved to a morning session.

Step 4: Allocate rooms and invigilators against the resolved grid

Whichever mechanism applies, JCQ's guidance is explicit that the candidate is told how the clash will be resolved, what to do on the day, and that the arrangement is confirmed in writing, not just discussed.

Only once clashes are resolved does the room and invigilator allocation mean anything; allocating against a draft that still has unresolved clashes means redoing it. Match each session to a room with enough exam capacity, keeping supervised-break candidates and any Saturday-morning sessions visible in the same pass so they don't quietly compete with the main series for the same rooms and staff.

Step 5: Publish, then confirm the exceptions in writing

Publish the timetable to candidates and staff. Every candidate whose exams were moved by a clash resolution gets that specific arrangement confirmed in writing, separate from the general publication, so nobody's personal exception is buried in a center-wide document.

Common mistakes

  • Placing exams before checking room and invigilator capacity. A grid that looks finished on the key dates can be unstaffable once the real numbers of usable rooms and available invigilators meet it.
  • Finding clashes too late to use every option. The forms and declarations a Saturday-morning move needs take time a week-before discovery does not leave.
  • Treating a resolved clash as informal. JCQ's rule is to confirm the arrangement in writing; a verbal heads-up is not the same thing if a candidate misses a session.
  • Missing late entry and withdrawal changes. A clash check run before the last entry amendment is a clash check against an exam timetable that no longer exists.

Where timetabling software fits

The mechanics above work on paper and in a spreadsheet, and many centers run them that way every series. What software changes is the cost of redoing the clash check after every entry amendment and re-checking room and invigilator capacity after every resolution, by hand, each time. Smootables places sessions against room, staff, and time constraints and surfaces clashes before a change is applied, the same approach it uses for the handoff into timetabling and for room and equipment constraints more generally; see how Smootables builds timetables for the detail.

Sources

Sources: JCQ, Managing timetable clashes (updated February 2024); JCQ, Key dates and timetables; JCQ, About us.

Frequently asked questions

What counts as an exam timetable clash?

One candidate entered for two or more exams scheduled at the same time on the same day. JCQ's rules for resolving it depend on the combined length of the exams and how many the candidate has that day.

Who is responsible for building the exam timetable?

Usually the exams officer or head of exams, sometimes a deputy head covering the role; the task sits with whoever the center has designated to hold entries, key dates, and room and invigilator capacity together.

Do all exam clashes need the awarding body's permission?

No. Same-session clashes of three hours or less, and same-session clashes resolved by moving one exam to the other session that day, need no awarding-body paperwork. Moving an exam to the next morning, including a Saturday, does need forms and signed declarations.

Does JCQ's clash guidance apply outside England, Wales, and Northern Ireland?

No. JCQ coordinates the GCSE and A-level boards for those three nations; it is the worked example here because it publishes the most detailed public, mechanical clash rules, not because it covers every center. Scotland runs National 5, Higher, and Advanced Higher exams under its own system, with its own timetable and clash process. Other countries' school-leaving exams (Ireland's Leaving Certificate, for example, set by the State Examinations Commission) run under their own national exam authority too. Wherever you sit, the build order above still applies; swap in your own authority's published clash rules for Step 3.

Can exam-timetabling software prevent clashes automatically?

Software can surface a clash the moment entries create one, which is faster than a manual check, but the resolution itself, and which JCQ mechanism applies, is still a human decision the rules above govern.

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